Bridge Name

Bridge No.

L8920 & L8921

Bridge Type

Both bridges are three – span, continuous concrete deck girder. Both carry vehicular and pedestrian traffic.

Bridge History

Bridges L8920 and L8921 are two of several bridges constructed between 1912 and 1916 as the Midtown Greenway depression was dug to run freight rail below street grade. The bridges were chosen to begin a long-term repair project to preserve the bridges along the corridor. The concrete deck was thickened by means of placing precast concrete panels below deck, in between the concrete girders, supporting them on a corbel, and then flooding the void with self-consolidating concrete. This took the loads off the deck and deteriorated concrete girders and shared them with the new precast concrete slabs. This “hidden” method lessened the impact on the historic value the bridge holds.

The bridges are a contributing resource to a NRHP (National Register of Historic Places) Historic District.

O.N.E. Involvement

O.N.E. designed and developed plans for the bridge rehabilitation along with the precast panels. Laser scan data was manipulated to measure each individual opening to allow shop level drawings to be generated for the precast panels.